Martin mixed sulfur (a yellow solid) with iron filings (a black solid) in a ceramic dish called a crucible. Then he separated them using a magnet. What kind of a change is this? change in state mixing and separation replacement synthesis

The correct answer would be the second option. It is mixing and separation that is happening in the sentence described. He mixed two different substances which has different physical properties. By taking advantage of the differences especially their magnetic properties, he separated the substances by using a magnet since the iron filings are attracted to the magnet.